1. Field of the Invention
This invention relates to weapon systems employing a liquid propellant, and particularly to an ignition mechanism for such systems.
2. Prior Art
Liquid propellant guns are well known, and are shown, for example, in U.S. Pat. No. 4,023,463 issued to D. P. Tassie on May 17, 1977; U.S. Pat. No. 4,051,762 issued to E. Ashley on Oct. 4, 1977: and in U.S. Ser. No. 178,254 filed by M. Bulman on Aug. 7, 1980.
Such guns, firing non-hypergolic propellants, require an initial pulse of hot, high pressure gas in the combustion chamber to start the firing process for each shot. For repetitive firing, sequential pulses must be provided. When pyrotechnic primers are utilized, the expended primer must be replaced after each shot as shown in U.S. Pat. No. 4,051,762, supra. Alternatively, some monopropellants may be ignited by adiabatic compression as shown in U.S. Pat. No. 3,366,058 issued to J. J. Scanlon on Jan. 30, 1968, U.S. Pat. No. 3,576,103 issued to P. B. Kahn on Apr. 27, 1971, and U.S. Pat. No. 4,231,282 issued to E. Ashley on Nov. 4, 1980. Even when an electric arc is utilized for ignition, the propellant must be confined and exposed to sufficient temperature and pressure for combustion of the entire charge to occur. Such a situation is more easily achieved in a bulk loaded system where the combustion chamber is completely filled with propellant. In a regenerative piston system, the combustion chamber is relatively empty of propellant at the time of ignition.
An object of this invention is to provide an electrical mechanism for the ignition of liquid propellants particularly adapted for use in regenerative piston systems.
A feature of this invention is the provision of an ignition mechanism for a main combustion chamber including an ignition antechamber having a first cross-sectional area, an electrode, and an inlet port for liquid propellant; a conduit having a length over diameter ratio greater than one, a second cross-sectional area which is less than said first area, and an inlet which opens into said ignition antechamber and an outlet which opens through an orifice into said main combustion chamber.